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From: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To: Arlie Davis <arlied@google.com>
Cc: netdev@vger.kernel.org, linux-parisc@vger.kernel.org
Subject: Re: Bug report (with fix) for DEC Tulip driver (de2104x.c)
Date: Fri, 20 Sep 2019 12:43:53 +0200	[thread overview]
Message-ID: <20190920104353.GA10706@alpha.franken.de> (raw)
In-Reply-To: <CAK-9enMxA68mRYFG=2zD02guvCqe-aa3NO0YZuJcTdBWn5MPqg@mail.gmail.com>

On Mon, Sep 16, 2019 at 02:50:53PM -0700, Arlie Davis wrote:
>     See section 4.2.2 for the specs on the transfer descriptor.
> 
> Here's my patch that fixes it:
> 
> diff --git a/drivers/net/ethernet/dec/tulip/de2104x.c
> b/drivers/net/ethernet/dec/tulip/de2104x.c
> index f1a2da15dd0a..3a420ceb52e5 100644
> --- a/drivers/net/ethernet/dec/tulip/de2104x.c
> +++ b/drivers/net/ethernet/dec/tulip/de2104x.c
> @@ -545,6 +545,7 @@ static void de_tx (struct de_private *de)
>         while (tx_tail != tx_head) {
>                 struct sk_buff *skb;
>                 u32 status;
> +               u32 control;
> 
>                 rmb();
>                 status = le32_to_cpu(de->tx_ring[tx_tail].opts1);
> @@ -565,7 +566,8 @@ static void de_tx (struct de_private *de)
>                 pci_unmap_single(de->pdev, de->tx_skb[tx_tail].mapping,
>                                  skb->len, PCI_DMA_TODEVICE);
> 
> -               if (status & LastFrag) {
> +               control = le32_to_cpu(de->tx_ring[tx_tail].opts2);
> +               if (control & LastFrag) {

how about just remove the complete if ? We know that we always
use one descriptor per packet and chip doesn't touch control
field. So I see no reason to check it here. Tulip driver for
2114x cards doesn't check it neither.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

      parent reply	other threads:[~2019-09-20 10:57 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-16 21:50 Bug report (with fix) for DEC Tulip driver (de2104x.c) Arlie Davis
2019-09-17 21:28 ` Andrew Lunn
2019-09-17 21:36   ` Arlie Davis
2019-09-17 22:51     ` John David Anglin
2019-09-18  5:56       ` Helge Deller
2019-09-18 13:27         ` Thomas Bogendoerfer
2019-10-03  1:29           ` Maciej W. Rozycki
2019-09-19 20:31         ` Sven Schnelle
2019-09-20 10:43 ` Thomas Bogendoerfer [this message]

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